LEMON Manuals: Even more car manuals for everyone
Home >> Lexus >> 1997 >> LX 450 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Circuit Tests >> DTC P0402: Excessive Exhaust Gas RECIRCULATION (EGR) Flow Detected >> Diagnosis & Repair (Using Toyota Scan Tool)

Diagnosis & Repair (Using Toyota Scan Tool)

  1. Connect scan tool. See Figure. Turn ignition on. Read EGR gas temperature. If EGR gas temperature is 302°F (150°C), go to step 4). If EGR gas temperature is not 302°F (150°C), go to next step.
    NOTE: If EGR temperature displayed is 318.7°F (159.3°C), a short circuit exists in EGR temperature sensor circuit.
  2. Disconnect EGR temperature sensor connector. Using scan tool, read EGR gas temperature. If EGR gas temperature is not 37.6°F (3.1°C), go to next step. If EGR gas temperature is 37.6°F (3.1°C), replace sensor and retest.
  3. Turn ignition off. Access ECM behind right instrument panel speaker. Disconnect ECM E4 connector. See Figure. Turn ignition on. Using scan tool, read EGR gas temperature. If EGR gas temperature is 37.6°F (3.1°C), locate and repair open circuit in wiring harness between ECM and EGR temperature sensor. If temperature is not 37.6°F (3.1°C), replace ECM and retest.
  4. Using scan tool, select ACTIVE TEST mode. Check operation of VSV when activated by scan tool. VSV is located under air intake chamber. Start and run engine. With EGR system off, air from VSV port "G" should flow from port "E". See Figure. With EGR system on, air from port "G" should not flow from port "E". If VSV operates as specified, check EGR valve. See SYSTEM/COMPONENT TESTS article. If VSV does not operate as specified, go to next step.
  5. Remove EGR VSV. Air intake chamber may have to be removed to access VSV. Using ohmmeter, measure resistance between VSV terminals. Resistance should be 30-34 ohms at 68°F (20°C). Check for continuity between each VSV terminal and body of valve. If continuity exists, replace VSV. If continuity does not exist, go to next step.
  6. Check for open circuit in wiring harness between VSV and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair wiring as necessary. If wiring harness is okay, replace ECM and retest.
scientia non olet · About LEMON Manuals